In general, a centrifugal filter is a device performing the functions of separation, purification, and concentration of liquids that are different in components and specific gravities by using a centrifugal force. The centrifugal filter is also used in filtering impurities out of oil (lubricants or fuel oil), used in engines, and used in various kinds of mechanical devices.
FIG. 1 is a sectional view showing the structure of the centrifugal filter according to a conventional art.
The centrifugal filter shown in FIG. 1 is used in filtering impurities out of oil for engines and mechanical devices.
The centrifugal filter includes: a shaft 10 provided with a flow path 11 therein through which oil is introduced; a rotor 20 configured to rotate around the shaft 10; a stand tube 30 configured to rotate around the shaft 10 with the rotor 20, the stand tube jetting the oil introduced through the shaft into the rotor; and a cover 40 receiving oil jetted from a nozzle 21 of the rotor by housing the rotor 20 therein, the cover including an oil inlet and an oil outlet.
The above-described centrifugal filter receives oil by a drive of a pump (not shown), and filters impurities from the oil by using centrifugal force. The centrifugal filter is configured in such a manner that the rotor rotates at high speed by using a reaction force produced during oil-jetting through the nozzle provided in the rotor.
Although the above-described centrifugal filter can separate and remove impurities in oil, it cannot remove water from the oil. Accordingly, an oil purification system using the centrifugal filter of the conventional art requires an additional oil-water separator.
FIG. 2 is a sectional view showing the structure of a centrifugal filter according to another conventional art.
The centrifugal filter shown in FIG. 2 can simultaneously remove impurities and water in oil, and more specifically, during the rotation of a rotor 50, an impurity A and water B are removed from the oil by being moved to an edge of an inside of the rotor 50 by centrifugal force. Accordingly, the water separated from the oil is discharged through a flow path 51 provided in the rotor, and when the impurity A accumulated on the edge of the inside of the rotor reaches a predetermined amount, an impurity discharge hole 52 is opened, and thus the impurity is discharged to the outside of the centrifugal filter.
As described above, the centrifugal filter has an advantage in that it is capable of removing water in oil even without using the additional oil-water separator. However, the centrifugal filter has an inconsistency in that it requires supplying water for the separation of water or removal of the impurities from oil, and further has a disadvantage in that an emulsion occurs due to the increase of a region on which water and oil come into contact with each other.